The subject disclosure relates to an improved method and apparatus for tufting to enable the production of an improved tufted product hithertofore not obtainable from commercial tufting machines.
In recent years the "Spanel Tufting System" involving multi-color tufting has been developed under the direction of Abram. N. Spanel, a coinventor of the subject disclosure. Multi-color tufting has been a primary objective of the system with the purpose to enable the tufting of different color yarns for each tufting stroke. Under such a system, the production of detailed colored pictorials can be readily accomplished since yarn selection means can be included to choose a particular yarn from a plurality of yarn choices for each of the tufting strokes. With a "Spanel" tufting machine having on the order of 1200 needles, if there is a choice of, for example, five or eight colors for each needle stroke of the 1200 needles, it readily can be appreciated that a painting or other picture can be precisely and accurately reproduced in the form of a tufted product.
More precisely, the Spanel system utilizes pneumatic means to transport yarn to tufting stations, either in metered lengths of unsevered yarn or discrete yarn bits. The yarn is then tufted by needle or other bit-applying means to a backing layer to form a tufted product such as a rug.
Aspects of the Spanel system are disclosed in U.S. Pat. No. Re. 27,165 and U.S. Pat. No. 3,554,147, such as the concept and fundamental apparatus for selecting one of an array of yarn color strands and then transporting the yarn strand or a severed yarn bit to a needle station for tufting. A number of Spanel improvement patents disclose improved means of selecting yarn for the tufting stations. Basically, however, in the Spanel patents, regardless of the type of yarn selection system, yarn strands were metered by metering devices and fed pneumatically to a magazine or collator with multiple selection yarn tubes either leading directly to tufting stations or merging into a common passageway leading to the tufting stations. The metering device in the aforementioned U.S. Pat. No. 3,554,147 includes yarn brakes and yarn pullers which are individually actuated but which co-act to meter a length of yarn for yarn selection. Thus these Spanel patents disclose apparatus to select and meter a length of yarn for each of the needle stations.
It now has been discovered that certain other developments when incorporated with the early Spanel techniques can be utilized to produce a product formerly not throught possible on a full-size commercial tufting machine. As will be discussed, these advances create a machine of precise exactitude which will effectively enable the positioning of all needle strokes, including the elimination of strokes to control density with the final product being a finely engineered tufted product superior to any other machine-made product.
The advancement over commercial machines of today, which attempt to control density is striking. Currently, density in most tufted products is controlled by the use of a pattern reader. A typical means of controlling pattern definition is the universal type patent attachment (UTPA) which comprises a series of knurled rolls that run in concert with each other. The rolls, which run at varying speeds, are a combination of knurled and smoothly polished members.
Specifically, a first roll will have areas of heavy knurls alternating with areas which are smoothly polished. A second abutting roll that is to run at a different speed from the first has exactly the same type alternating surface finish, except the polished areas are disposed opposite from the knurled areas of the first roll, and the knurled areas opposite the polished. A deflector finger is positioned above the two rolls which deflects the yarn to the right or left to pick up high or low speed to enable a high and low pattern. This pattern becomes a mirror image since a first yarn is taken from the rolls to the right hand side of the machine and the second yarn to the left hand side within the capability of yarn selectors. A product can thus be obtained with no repeat from the center line to one side of the rug, however, the exact pattern will be produced on the other side of the rug. It will be appreciated that in such a conventional tufting machine since the yarn must be threaded continuously in the tufting needles, precise control of density is impossible since the length of each tuft can not be controlled with each descending needle stroke.
Furthermore, as will be discussed in detail, while present day patterning techniques are limited to high-low tuft production, in the Spanel operation disclosed herein, in addition to controlling the length of yarn for each needle stroke, it is also possible to control the type needles to be used, whether an individual needle is used, or whether a particular needle is fed yarn even if the needle is automatically being used. For example, if a shag carpet is being tufted and in view of the length of the yarn tuft it is desired to reduce the yarn density, a needle can be removed from operation as disclosed herein or the tuft strokes can be carried out with unthreaded needles.
Thus, the subject specification will disclose the apparatus and method to tuft with all 1200 needles, or every second or third needle if desirable. Such capability does not exist in present day commercial machines since the needles are threaded continuously with yarn and are driven by a needle bar which constantly reciprocates.
For example, if a carpet mill is running a five-sixteenths inch gauge carpet and it is desirable to run a five-eighths inch gauge carpet, it is necessary to seize and cut every other yarn which extends to the needles and tie the cut ends to the header bar. In each such machine, there are approximately 608 ends of yarn leading into the machine from the creel and accordingly, approximately 304 must be removed. These yarns must also be unthreaded from the yarn feed rolls and from the needles with care being taken to ensure that the proper yarns are removed. When it is desired to return to running five-sixteenths inch gauge carpet, the needles and feed rolls must be rethreaded, thus in practice, because of time considerations usually such machine changes are not made. Furthermore, it will be realized that changes cannot be made while the machine is running and accordingly, the production of a rug having total control of multiple levels of tufts is not possible by present commercial techniques. On the other hand, as disclosed in the subject specification, it becomes possible to not only quickly change the length and type of tuft for each needle station while eliminating tufting at certain stations, but such change may also be effectuated during the tufting of a single carpet.
The product of the subject disclosure can further be improved over prior art products by the ability to precisely control feeding of the backing layer. The backing layer of the subject disclosure is advanced incrementally and this advancement can be controlled so as to lengthen the distance between successive needle strokes as is desirable in the case where shag carpet is being tufted. In contrast most conventional tufting operations utilize uncontrollable continuous feed of the backing layer.
Additionally, a backing shifter is disclosed herein to enable the lateral shifting of the backing layer. Backing shifters per se are well known in the carpet industry with the first ones being called "wavy-line" units. An eccentric wheel was used with an adjustable slot in the middle to enable adjustment of the shift to be made and once adjusted, the machine was permitted to keep running to produce what was known as wavy-line carpet. Such a procedure became well known with chenille bedspreads.
As used herein, the backing shifter is used to supplement needle positioning which is a function of the control of yarn density. With programming and complete adjustability of the backing shifter, it will be appreciated that not only is the ability available to select the use of needles, and the type and size of yarn to be tufted, but also by virtue of the backing feeding and backing shifting control, the precise location or placement of the needles into the backing layer is obtained.
The improvements with the backing shifter of the subject disclosure can best be appreciated by viewing the use of backing shifters in conventional tufting machines. Conventional tufting machines, usually have needle plates placed below the needles with yarn being fed downwardly therethrough. In a conventional loop pile machine, the tuft hook is positioned below the needle plate. The backing flows over the top of the needle plates with backing fingers being used to support the backing and support the penetration load of the needles. Since the loops are continuous as they are formed on the face below the backing, it is not possible to effectuate the backing shift in the needle area because of the needle plate location. Accordingly, in a conventional tufting machine, the pin roll which is used is positioned at a distance permitting tangential engagements of the backing layer only. Thus, with the pin roll placed approximately two and a half inches from the needle location, it is necessary to move the backing approximately three-quarters of an inch to achieve a three-sixteenths inch movement at the needles. This is due to both the location of the pin rolls and the natural drag which is encountered because the loops are hooked onto the needle plate fingers in the proximity of the needle station.
As disclosed herein, since the pin roll is placed in close proximity to the needles, backing layer control very close to the needle station can be achieved. In view of this positioning of the pin roll, since there is no drag because of the nature of the tufting operation, it is geometrically predictable precisely how far the backing layer will move adding to the ability to precisely control a tufted product. Further, in the subject specification, the backing layer is advanced incrementally as distinguished from the conventional machine where the backing is in continuous motion creating a much higher drag factor.